Hi.
As discussed with Marc, I'm suggesting to mark user-provided
delete operators with DECL_SET_IS_OPERATOR_DELETE in order to allow
possible DCE for it. I've checked that clang can also optimize that
situation out.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
gcc/cp/ChangeLog:
2019-07-30 Martin Liska <mli...@suse.cz>
* decl.c (grok_op_properties):
Mark DECL_SET_IS_OPERATOR_DELETE for user-provided delete operators.
gcc/testsuite/ChangeLog:
2019-07-30 Martin Liska <mli...@suse.cz>
* g++.dg/cpp1y/new2.C: New test.
---
gcc/cp/decl.c | 5 +++-
gcc/testsuite/g++.dg/cpp1y/new2.C | 39 +++++++++++++++++++++++++++++++
2 files changed, 43 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/new2.C
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 9fa090c8767..bc438d23db3 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13670,7 +13670,10 @@ grok_op_properties (tree decl, bool complain)
}
if (op_flags & OVL_OP_FLAG_DELETE)
- coerce_delete_type (decl, loc);
+ {
+ DECL_SET_IS_OPERATOR_DELETE (decl, true);
+ coerce_delete_type (decl, loc);
+ }
else
{
DECL_SET_IS_OPERATOR_NEW (decl, true);
diff --git a/gcc/testsuite/g++.dg/cpp1y/new2.C b/gcc/testsuite/g++.dg/cpp1y/new2.C
new file mode 100644
index 00000000000..926e7960528
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/new2.C
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=c++17 -fdump-tree-cddce-details" } */
+
+#include <cstdio>
+#include <cstdlib>
+#include <new>
+
+void* operator new(std::size_t sz)
+{
+ std::printf("global op new called, size = %zu\n", sz);
+ void *ptr = std::malloc(sz);
+ if (ptr)
+ return ptr;
+ else
+ throw std::bad_alloc{};
+}
+
+void operator delete(void* ptr) noexcept
+{
+ std::puts("global op delete called");
+ std::free(ptr);
+}
+
+void
+new_primitive_load() {
+ int *x = new int;
+ int tmp = *x;
+ delete x;
+}
+
+void
+new_array_load() {
+ int *x = new int[10];
+ int tmp = x[4];
+ delete [] x;
+}
+
+/* { dg-final { scan-tree-dump-times "Deleting : _\\d+ = operator new" 2 "cddce1"} } */
+/* { dg-final { scan-tree-dump-times "Deleting : operator delete" 2 "cddce1"} } */
